Study Finds Periods Start Earlier in Girls Who Drink a Lot of Sugary Drinks. What Does This Mean for Breast Cancer Risk?

A new study released last week in the journal Human Reproduction has found that regularly drinking sugar-sweetened beverages - like sodas and fruit drinks - may cause girls to start their menstrual periods at earlier ages.

The study, a spin off of the long-running Nurses' Health Study at Harvard University, followed around 5,000 9 - 14 year old girls for up to five years - tracking their food, beverage intake, and menstrual status along the way. Researchers found a distinct link between regularly drinking sugary beverages and the age periods started (technically called, menarche). Those girls who drank more than 1.5 servings of soda or fruit drink each day started their period on average at 12.8 years, about three months earlier than girls drinking 2 or fewer servings each week. Even after taking body mass index (BMI) into account, which is linked to age at menarche, the same general association remained.

So, what does this have to do with cancer?

There's increasingly good data that early life plays a particularly important role in later adult breast cancer risk, something we've certainly written about here on CNiC. This new study provides further evidence that the choices our children make - and that we help them make - can have implications later in life. The earlier menarche begins, the greater the lifetime exposure to estrogen and other reproductive hormones, which is a key risk factor for breast cancer.

And while the age differences at menarche weren't huge in this new study - meaning the impact of sugary drinks on overall breast cancer risk would likely be modest - cutting back on sodas and fruit drinks still provides an easy way to help lower risk, which when combined with other healthy choices in youth - like choosing plant-based foods and getting regular exercise - can have an important overall impact on later breast health.

A healthy lifestyle started in mid-life - when most women are likely to actually start thinking in earnest about their breast health - can cut the risk of breast cancer by 50 percent. Starting healthy behaviors in childhood and continuing them throughout adulthood can cut risk by close to 70 percent (see figure). And the steps are surprisingly simple, with one of the easiest being substituting water for sugary sodas and fruit drinks.